Excel Sales Forecasting For Dummies, 2nd Edition

Chapter 12

Entering the Formulas Yourself

IN THIS CHAPTER

Making sense of Excel formulas

Accepting some help from Excel

Getting familiar with array formulas

Trying your hand at regression functions

This chapter starts with a brief review — or overview — of the rules for Excel formulas. As you get more and more comfortable with quantitative forecasting, you’re likely to find yourself wanting to rely less on tools such as the Data Analysis add-in, and more on writing your own formulas.

Excel has hundreds of prefabricated formulas, called functions. A good example is the AVERAGE function. All you need to do is refer to the function in a worksheet cell and point it at a range of cells with numbers in them. The AVERAGE function adds up the values in that range of cells and divides by the number of values.

You get more information about Excel functions that are useful in forecasting in this chapter. Besides the AVERAGE function, there are some functions that are important in forecasts that use regression.

Some functions require that you array-enter them if they’re to return the results you’re after. This chapter goes into some detail about how to array-enter a formula, whether or not the formula contains a function.

About Excel Formulas

Formulas are at the heart of Excel, which makes it difficult to understand why 80 percent of Excel worksheets contain no formulas, only static values like 14 or Smith (that’s what a market research study determined a few years back). Formulas, together ...